This invention relates generally to prosthetic devices, and more particularly, to a life-like prosthetic device, such as a hand, finger, or a portion thereof, which can be worn by a person to simulate, and insofar as possible, to substitute physically for a missing or damaged body part.
The need for life-like prosthetics has long been recognized and various attempts have been made to produce prosthetic devices which restore some utility of the missing part to the amputee. Possibly of equal significance today, is the need to restore near-normal appearance to satisfy the psychological requirements of persons missing visible body parts by restoring insofar as possible, the devastated body image, particularly with respect to body members at or below the forearm. Many amputees have an extreme need for an assisting prosthetic device which has a natural and life-like appearance to help restore damaged body image while minimizing attention drawn to their loss which is viewed as a serious stigma. It is unrealistic in our mobile and competitive society not to recognize that the stigma of dismemberment is a serious socio-economic handicap for the amputee.
One prior art attempt at producing a life-like hand prosthesis is described in U.S. Pat. No. 2,453,604. In accordance with this known system, a product is produced which is intended to resemble a human hand, and which may be used either in the form of a glove for covering mechanical apparatus, or which may be filled to form an artificial hand. In accordance with this known system, a coating of latex is applied in a known manner, such as by spraying, to a human hand which serves as the model from which the prosthetic device is formed. The sprayed-on material is then peeled off of the human hand, in the same manner that a rubber glove is removed, and various painting procedures are performed while the glove is in an inside-out state.
In accordance with a further known method of making a cosmetic glove, the mold is produced by electrodeposition, and a cosmetic glove formed on a vinyl chloride polymer or co-polymer is then cast therein. The resulting thin glove is then pigmented using soluble colors to diffuse into the resin which forms the glove, or alternatively, insoluble colors are used. The glove is turned inside-out during the painting process to facilitate the application of pigmentation and the glove is subsequently reversed so that the colors are located on the inside surface of the glove during its usage.
None of the artificial or prosthetic items produced in accordance with the known methods have perfection of life-like or natural characteristics, nor do any of the devices of known methods using polyvinyl chloride have a practical service life with regular utilization.
It is, therefore, an object of this invention to provide a reliable, safe, fast, versatile and economical method of producing prosthetic devices such as an artificial hand or finger, which are near-natural and alive in appearance with, or without, the incorporation of various mechanical aids to improve their utility according to the individual requirements.
It is also an object of this invention to provide a reliable method for producing coloration of prosthetic devices mimicking the natural method of skin coloration to result in an appearance of natural skin with translucency, shading and variations in coloration as occurs in the wide variety of individual human skin colors.
It is also an object of this invention to provide a method for forming a prosthetic device having the resilient characteristics of the tissue of the body member after which it is being modeled.
It is still a further object of this invention to provide a prosthetic device having a fingernail of normal appearance and feeling to touch, which is inlayed for normal definition with attachment being accomplished in a secure and durable manner.
Another object of this invention is to provide a method wherein artificial body members can be constructed of materials that are non-irritating to the skin, durable, stain resistant and repairable while having a relatively long service life.
It is still another object of this invention to facilitate fabrication of a prosthetic device by providing a rapid, practical method for reliably removing solvents from chemical dispersions of the elastomers or other materials from the prostheses.
It is a further object of this invention to provide a reliable method of procurring ventilation ports in the metallic molds for a prosthetic device, by providing ports of optimal size and position without risk of damage to the delicate interior surface details of the seamless metal molds.
It is yet a further object of this invention to provide a method of forming prosthetic devices wherein a thin and delicate outer layer of the prosthetic device is easily released from a seamless negative metal mold from which the finest of details are reproduced faithfully.
It is another object of this invention to provide a reliable and expedient prefabricating method of filling the interior of the thin outer portion of the prosthesis, that corresponding to human skin, with a material of variable density, shape and other characteristics as determined by the individual needs and to install such perfabricated internal unit without changes in the shape, color or other details of the thin and pliable outer shell and with provisions of the method to also permit incorporation of metal stabilizers for the parts or a variety of mechanical assisting devices.
It is still another object of this invention to provide a reliable method of producing the prosthetic outer shell consistently free of entrapped bubbles or other defects and to do so in a short period of time.